The present invention relates to a pattern data conversion processing system, used in a pattern conversion mechanism such as a page printer control mechanism, for converting character pattern data of a predetermined matrix to dot data.
In a conventional printer control mechanism for printing a character in a dot matrix form, when the dot matrices of all the characters to be printed have an identical number of dots, an address corresponding to this number of dots is generated so as to easily write the respective character patterns in a memory. However, when different types of dot matrix formats are used, write access of the memory is very complicated. In particular, in order to perform, with a single circuit, processing (e.g., longitudinal or transverse double elongation or enlargement of a character) of characters with different dot matrix formats, different dot pattern data are generated, making the circuit arrangement and control procedures very complex. Therefore, a common processing circuit cannot be used, resulting in inconvenience.
In a conventional printer for printing characters in a dot matrix, each character has a 24.times.24 dot matrix printing format on slips, vouchers or the like, and a 32.times.32 dot matrix when printed on normal documents. In order to arbitrarily print characters having two different dot matrix formats with a single printer, two types of character generators for storing a large number of kanji characters, numerals, letters, hiragana characters and katakana characters are required for each dot matrix format. As a result, the character generator section is very costly.
After double elongation conversion (i.e., double elongation of the height or width of a character) of a character pattern generated from the corresponding character generator is performed in a conventional dot matrix printer, the converted character pattern is printed out. However, in order to perform double elongation conversion of the character patterns generated from the two character generators for storing patterns of different dot matrix formats, two independent conversion circuits are required, complicating the circuit arrangement and control procedures and greatly increasing the cost.
When pattern data having a predetermined dot matrix format is read out from a memory and written into the same memory or another memory, bit shifting of a write position by an arbitrary number of bits is often required. Conventionally, one-word pattern data is read out from the memory and written into a shift register. The one-word pattern data is shifted by an arbitrary number of bits in the shift register, and the shifted data is then written into the memory.
According to the conventional configuration described above, however, input and shift control operations of the shift register are complex.
A conventional page printer has an image memory for storing one-page pattern data. When pattern data is written in a predetermined area of the image memory, the pattern data accessed, in units of words, from the image memory is superposed on the pattern data shifted in accordance with the write position of the image memory, and the resultant data is written into the image memory. The conventional system requires a latch for latching the pattern data read out from the image memory, a latch for latching the pattern data to be written in the image memory, and a latch for latching the superposed data. As a result, the circuit arrangement is complicated.
In a conventional printer for printing each character in a dot matrix, characters are rotated in accordance with either a vertical or a horizontal printout direction. A character pattern generated from a character generator is rotated, and the rotated pattern is printed. Character rotation is performed with hardware. When character patterns are rotated at the different rotation angles of 90 degrees counterclockwise, and 90 and 180 degrees clockwise, many conversion pattern generators for generating converted patterns having predetermined rotational angles, and many control circuits for writing the respective converted patterns in the printing buffers are required, resulting in an intricate control operation.
A conventional page printer is used for printing a large number of sheets, as in the compilation of a printed document. However, in the conventional page printer, no consideration is made for binding margins (i.e., gutters) for compiling. For this reason, some of the characters are concealed within a binding margin. Character rotation and page memory write access must be sequentially performed in accordance with which side of a sheet is to be used as a binding margin and which one of either a vertical or a horizontal printout direction is selected. However, these considerations have never been dealt with in conventional page printers.
It takes time to retrieve a desired page while the printed sheets are stacked. When the printed sheets are compiled and bound, a desired page cannot be found when the book is closed.